1961: mRNA Ferries Information

Sydney Brenner, Francois Jacob, and Matthew Meselson discovered that mRNA is the molecule that takes information from DNA in the nucleus to the protein-making machinery in the cytoplasm. When DNA was determined to be the hereditary material, scientists wondered how DNA, which is sequestered in the nucleus, directs the formation of proteins, when protein synthesis occurs in the cytoplasm. RNA is the intermediary molecule. Specifically, messenger RNA, or mRNA, ferries information from the nucleus to the cytoplasm.

RNA is chemically similar to DNA except that:

The sugar in its nucleotide building blocks is ribose and not deoxyribose.

RNA uses the nucleotide base uracil instead of thymine. But like thymine, uracil can pair with adenine.

RNA, especially mRNA, tends to be single-stranded, not double-stranded like DNA.